In the prior art, different bending machines for bilateral processing of workpieces cut to length are known.
DE 3922326 C2 describes a bending machine comprising two bending heads mounted to robot arms, wherein up to four axes of rotation are present for positioning the tool on the workpiece. Each robot arm has its own guide assigned to it, allowing said robot arm to be displaced parallel to the workpiece. Between the guideways of the robot arms, a gripping unit is provided for fixing the respective workpiece to be processed, which gripping unit can be lowered, in which case a bending tool then functions as gripping means. The use of bending robots for bending the workpiece to be shaped is very complex, so that due to the workpiece to be processed being held only at its center or even only due to the fixation of the workpiece when lowering it, undesired vibrations may occur at the bending tool in the longitudinal direction of the workpiece, which has an unfavorable influence both on the bending accuracy as well as on the possible speed of the bending operations and, thus, on the performance of the machine.
A bending device is known from DE 4300311 C2, which bending device comprises one or more gripping units that can be displaced in one plane, said gripping units transporting the workpiece to be processed between parallel bending stations, each of said bending stations carrying out one single bending operation. During bending itself, the tool is fixed by the clamps of the bending tool of the respective bending station. In this case, the bending heads are fitted on a vertically displaceable table so as to enable transport of the workpieces without vertically moving the gripping units. This known machine is very complex in terms of its overall structure and does not allow the processing of wire directly from the coil.
DE 19630023 A1 describes a bending system comprising a plurality of bending stations in which a workpiece can be processed first on one side and then on the other or, in the case of bending in one plane, on both sides at the same time. In this case, a plurality of gripping units are provided to convey the workpiece between the individual bending stations, which grippers are also used to rotate the workpieces. The bending heads are arranged for displacement parallel to the workpiece axis. All gripping units are mounted to a portal. This known bending machine also has a very complex structure, which applies particularly to the arrangement of the gripping units on a portal construction. This known bending machine also does not enable processing of wire drawn directly from the coil.
The bending machine known from DE 20 2004 011 947 U1 also serves to process elongated workpieces in a plurality of stations. In this case, each station comprises a central gripping unit and two bending heads mounted laterally thereof, which are displaceable on a common bed guide as is the gripping unit. In addition, a pivotable transfer device is provided by which the workpiece can be pivoted from the first processing station to the second, parallel processing station. The transfer device may be the gripping unit at the same time. This known machine works serially from out of a magazine and likewise does not allow the processing of wire directly from the coil.